package com.itheima.ydd.controller;

import com.itheima.ydd.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.UUID;

//文件上传和下载
@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {
    @Value("${ydd.path}")
    private String basePath;

    @PostMapping("/upload")
    //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
    public R<String> upload(MultipartFile file){//这里的参数名必须与前端的name名保持一致
        log.info(file.toString());
       //原文件名
        String originalFilename = file.getOriginalFilename();
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));

        //使用UUID重新生成文件名，方式文件名称重复造成文件覆盖
        String fileName = UUID.randomUUID().toString()+suffix;

        //创建一个目录对象，目的是判断这个临时文件目录存不存在
        File dir = new File(basePath);
        //判断当前目录是否存在，不存在进行创建
        if(!dir.exists()){
            dir.mkdirs();
        }
        //将临时文件转存到指定路径
        try {
            file.transferTo(new File(basePath+fileName));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return R.success(fileName);
    }

    //文件下载
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response){

        try {
            //通过输入流读取文件
            FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));

            //通过输出流将图片写到网页上
            ServletOutputStream outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while ((len=fileInputStream.read(bytes)) != -1){
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }

            outputStream.close();
            fileInputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }


    }
}
